HBO brandished its Valyrian legal swords against a Brooklyn bar, forcing it to end the Sunday night “Game of Thrones” viewing parties it’s been hosting for two years.

“As a pay subscription service, HBO should not be made available in public establishments,” HBO said after sending an April 15 cease-and-desist letter to Videology Bar & Cinema in Williamsburg.

James Leet, co-owner of the Bedford Avenue bar, said the letter was as jarring as Season 3’s “Red Wedding.”

“We feel really bad that we’re not allowed to show it. We don’t have a choice,” Leet said.

By Sunday afternoon, Videology posted a message to Facebook reading: “Sorry guys. No Game of Thrones showing tonight. Or ever. Not our choice. #WinterIsHere.”

William MillerRegulars, who were shown “Mad Men’’ instead, were furious.

“Sending a bar a cease-and-desist letter is like saying I can’t invite my friends to my house to watch ‘Game of Thrones’ because they haven’t paid for it. It’s just wrong,” said Ian Phillips, 27.

A “Game of Thrones” viewing at Professor Thom’s in the East Village.William C. Lopez

“What about the people e-pirating the show online?”

HBO explained it monitors bars and eateries to find viewing parties and relies on tips to catch filchers.

“This is nothing new, as we have taken such actions for well over a decade,” the cable giant said.

In the early 2000s, the network ordered up hits on several Chicago gin mills showing “The Sopranos.”

Videology shot to the top of HBO’s list because it screens the show in a theater connected to the bar, a source told The Post.

“The trigger for HBO is establishments attempting to make a profit off the program,” the source said.

Professor Thom’s in the East VillageWilliam C. Lopez

Still, dozens of bars across the city continue to host “Game of Thrones” nights.

The Bedford, 10 minutes from Videology, hasn’t gotten any letters and plans to continue showing the series for the rest of this season.

Staffers at Greenpoint Heights, another bar with viewing parties, said they haven’t heard from HBO.

Professor Thom’s in the East Village brings in an army of Khaleesi worshippers every Sunday. Owner Peter Levin pours free shots if a character is killed or a dragon appears, but said he doesn’t charge admission.